Radio-frequency identification (RFID) tags have been widely used to identify and track objects. An RFID tag is attached to, or incorporated in, a physical object and has an antenna for communicating with a remote receiver through RF (radio-frequency electromagnetic waves). The RFID tag may communicate a unique identifier, representative of the RFID tag and, therefore, of the individual physical object. The RFID tag may be a passive RFID tag that generates power for its operation upon receipt of an incident electromagnetic wave generated by an external source and of a proper frequency corresponding to the sensitivity of the antenna. Alternatively, the RFID tag may be an active RFID tag, accommodating its own power supply, e.g., a battery or an energy scavenger, for autonomous operation.
An RFID tag can be combined with a sensor so as to implement a low-cost remote sensor for use in telemetry applications. For example, the Wireless Identification and Sensing Platform (WISP) is a type of passive RFID tag that is configured for supporting sensing, e.g., of temperature or of acceleration, for local processing of a sensor signal, and for communicating the processed signal via RF to an external receiver.
RFID technology is helping to transform logistics by providing a means of tracking and tracing individual products throughout the supply chain. Nowadays, increasingly more e research and development is ongoing in the integration of active RFID tags with sensors that monitor the quality of the product. In recent years, wireless sensors have been adopted in food processing to monitor and control the quality attributes of food products. For example, a temperature sensor can be inserted into a food item for recording the temperature over time, and for transmitting the temperature data wirelessly to a central controller.
RFID tagging has been accepted as a new technology for a well-structured traceability system on data collecting, and human, animal and product tracking. It has been projected that the applications of RFID will grow rapidly in the next 10 years with a compound annual revenue growth rate (2003-2010) of 32.2% see, e.g., N. Wang et al., Computers and Electronics in Agriculture 50 (2006), pp. 1-14.